For stabilizing and fixing fractures it is known to employ bone plates fixed on the bone by means of suitable fastening elements such as, for example, bone screws, along with pins, bolts or other bone anchors. To guarantee secure fixation of the bone fragments to each other and of the bone plate to the bone, the bone anchors must be incorporated into the bone precisely. In particular, the angles at which the bone anchors are driven into the bone are of great importance.
Hence, it is known, for example, from EP 1 741 397 A1 to provide bone plates with through holes having a variable-angle portion which allows a threaded head of a locking screw to be received and locked in a threaded bone plate hole at different angles relative to a hole axis of the threaded bone plate hole. The threaded bone plate hole may have rib-like or thread structures interrupted by recesses that extend radially away from the hole axis, whereby one or a plurality of the recesses extends in the direction of a longitudinally running side edge of the bone plate. However, a problem arises here that, in particular in the region of the recesses of the variable-angle through hole that extend in the direction toward the side edge, stress peaks may occur when a bending load is placed on the bone plate. Because a bone plate is usually attached to the side of the bone that is under stress, the stress peaks occur in particular on the plate's upper side, i.e., the surface of the bone plate that faces away from the bone, when the bone plate is mounted to the bone.
The object of the present invention is to provide a bone plate having a variable-angle through hole wherein stress peaks that occur in the region of the variable-angle through hole upon a bending load on the bone plate are reduced.